Posterior Fossa Decompression with or without Duraplasty for Chiari Type I Malformation with Syringomyelia


About this study

The purpose of this study is to determine whether a posterior fossa decompression or a posterior fossa decompression with duraplasty results in better patient outcomes with fewer complications and improved quality of life in those who have Chiari malformation type I and syringomyelia.

Participation eligibility

Participant eligibility includes age, gender, type and stage of disease, and previous treatments or health concerns. Guidelines differ from study to study, and identify who can or cannot participate. There is no guarantee that every individual who qualifies and wants to participate in a trial will be enrolled. Contact the study team to discuss study eligibility and potential participation.

Inclusion Criteria:

  • Age ≤21 years old
  • Chiari malformation type I with ≥5 mm tonsillar ectopia
  • Syrinx diameter (recorded as the greatest antero-posterior or transverse diameter) 3-9 mm
  • MRI of the brain and cervical and thoracic spine are required prior to surgery and available to be shared with the DCC

Exclusion Criteria:

  • Syrinx <3 mm and/or ≥10 mm
  • Neuro-imaging demonstrating basilar invagination (position of the superior tip of dens  ≥5 mm above Chamberlain’s line)
  • Neuro-imaging demonstrating clival canal angle <120°
  • Prior PFD, PFDD, or other surgery at the craniovertebral junction
  • CM+SM secondary to other pathology (e.g. a tumor)
  • Unable to share pre-decompression MRI of the brain and cervical and thoracic spine
  • Patients who do not wish to participate

Participating Mayo Clinic locations

Study statuses change often. Please contact the study team for the most up-to-date information regarding possible participation.

Mayo Clinic Location Status Contact

Rochester, Minn.

Mayo Clinic principal investigator

David Daniels, M.D., Ph.D.

Contact us for the latest status

Contact information:

Adam Loudermilk

(507) 422-0718

More information


  • OBJECT The purpose of this study was to design and validate a patient-reported health-related quality of life (HRQOL) instrument for pediatric Chiari Type I malformation (CM-I), the Chiari Health Index for Pediatrics (CHIP). METHODS The CHIP has 45 items with 4 components making up 2 domain scores, physical (pain frequency, pain severity, nonpain symptoms) and psychosocial; physical and psychosocial scores are combined to create an overall HRQOL score. Increasing scores (0 to 1) represent increasing HRQOL. Fifty-five patients with CM-I (mean age 12 ± 4 years, 53% male) were enrolled and completed the CHIP and Health Utilities Index Mark 3 (HUI3). Twenty-five healthy controls (mean age 11.9 ± 4 years, 40% male) also completed the CHIP. CHIP scores were compared between these groups via the Mann-Whitney U-test. For CHIP discriminative function, subscore versus presence of CM-I was compared via receiver operating characteristic curve analysis. CHIP scores in the CM-I group were stratified by symptomatology (asymptomatic, headaches, and paresthesias) and compared via Kruskal-Wallis test with Mann-Whitney U-test with Bonferroni correction (p < 0.0167). CHIP was compared with HUI3 (Health Utilities Index Mark 3) via univariate and multivariate linear regression. RESULTS CHIP physical and psychosocial subscores were, respectively, 24% and 18% lower in CM-I patients than in controls (p < 0.001); the overall HRQOL score was 23% lower as well (p < 0.001). The area under the curve (AUC) for CHIP physical subscore versus presence of CM-I was 0.809. CHIP physical subscore varied significantly with symptomatology (p = 0.001) and HUI3 pain-related quality of life (R(2) = 0.311, p < 0.001). The AUC for CHIP psychosocial subscore versus presence of CM-I was 0.754. CHIP psychosocial subscore varied significantly with HUI3 cognitive- (R(2) = 0.324, p < 0.001) and emotion-related (R(2) = 0.155, p = 0.003) quality of life. The AUC for CHIP HRQOL versus presence of CM-I was 0.820. Overall CHIP HRQOL score varied significantly with symptomatology (p = 0.001) and HUI3 multiattribute composite HRQOL score (R(2) = 0.440, p < 0.001). CONCLUSIONS The CHIP is a patient-reported, CM-I-specific HRQOL instrument, with construct validity in assessing pain-, cognitive-, and emotion-related quality of life, as well as symptomatic features unique to CM-I. It holds promise as a discriminative HRQOL index in CM-I outcomes assessment. Read More on PubMed
  • To develop evidence-based treatment guidelines for Chiari malformation type 1 (CM-1), preoperative prognostic indices capable of stratifying patients for comparative trials are needed. Read More on PubMed
  • Chiari malformation Type I (CM-I) is a common and often debilitating neurological disease. Efforts to improve treatment of CM-I are impeded by inconsistent and limited methods of evaluating clinical outcomes. To understand current approaches and lay a foundation for future research, the authors conducted a systematic review of the methods used in original published research articles to evaluate clinical outcomes in patients treated for CM-I. Read More on PubMed
  • Chiari malformation Type I (CM-I) is a hindbrain disorder associated with elongation of the cerebellar tonsils, which descend below the foramen magnum into the spinal canal. It occurs in children and adults. Clinical symptoms mainly develop from alterations in CSF flow at the foramen magnum and the common subsequent development of syringomyelia. Read More on PubMed
  • Chiari malformation type I (CM1) is a common and often debilitating neurosurgical disease. Whether to treat CM1 patients with a traditional posterior fossa decompression with duraplasty (PFDD) or a less invasive extradural decompression (PFDO) is controversial. The purpose of this study was to compare clinical outcome and syrinx resolution between the two procedures. Read More on PubMed
  • Historically, assessment of clinical outcomes following surgical management of Chiari malformation Type I (CM-I) has been challenging due to the lack of a validated instrument for widespread use. The Chicago Chiari Outcome Scale (CCOS) is a novel system intended to provide a less subjective evaluation of outcomes for patients with CM-I. The goal of this study was to externally validate the performance of the CCOS. Read More on PubMed
  • Chiari malformation Type I (CM-I) is a developmental abnormality often associated with a spinal syrinx. Patients with syringomyelia are known to have an increased risk of scoliosis, yet the influence of specific radiographically demonstrated features on the prevalence of scoliosis remains unclear. The primary objective of the present study was to investigate the relationship of maximum syrinx diameter and tonsillar descent to the presence of scoliosis in patients with CM-I-associated syringomyelia. A secondary objective was to explore the role of craniovertebral junction (CVJ) characteristics as additional risk factors for scoliosis. Read More on PubMed
  • Dural splitting decompression may be an effective and safe treatment for Chiari I malformation. Read More on PubMed
  • Monitoring and recording of complications in pediatric neurosurgery are important for quality assurance and in particular for improving outcomes. Lack of accurate or mutually agreed upon definitions hampers this process and makes comparisons between centers, which is an important method to improve outcomes, difficult. Therefore, the Canadian Pediatric Neurosurgery Study Group created definitions of complications in pediatric neurosurgery with consensus among 13 Canadian pediatric neurosurgical centers. Read More on PubMed
  • To assess the outcome in patients with syrinx and non-syrinx associated Chiari malformations undergoing Foramen Magnum Decompression (FMD). Read More on PubMed
  • The purpose of this study was to report the results of a survey of the American Society of Pediatric Neurosurgeons (ASPN) on treatment of Chiari malformation Type I (CM-I) with syringomyelia. Read More on PubMed
  • Few studies are available that directly compare dural opening with and without additional intradural maneuvers. Therefore, the current review analyzed the available literature regarding this topic. Read More on PubMed
  • The optimal surgical management of Chiari malformation (CM) is evolving. Evidence continues to accrue that supports decompression without duraplasty as an effective treatment to achieve symptomatic relief and anatomical decompression. The risks and benefits of this less invasive operation need to be weighed against decompression with duraplasty. Read More on PubMed
  • Chiari disease (or malformation) is in general a congenital condition characterized by an anatomic defect of the base of the skull, in which the cerebellum and brain stem herniate through the foramen magnum into the cervical spinal canal. The onset of Chiari syndrome symptoms usually occurs in the second or third decade (age 25 to 45 years). Symptoms may vary between periods of exacerbation and remission. The diagnosis of Chiari type I malformation in patients with or without symptoms is established with neuroimaging techniques. The most effective therapy for patients with Chiari type I malformation/syringomyelia is surgical decompression of the foramen magnum, however there are non-surgical therapy to relieve neuropathic pain: either pharmacological and non-pharmacological. Pharmacological therapy use drugs that act on different components of pain. Non-pharmacological therapies are primarily based on spinal or peripheral electrical stimulation. It is important to determine the needs of the patients in terms of health-care, social, educational, occupational, and relationship issues, in addition to those derived from information aspects, particularly at onset of symptoms. Currently, there is no consensus among the specialists regarding the etiology of the disease or how to approach, monitor, follow-up, and treat the condition. It is necessary that the physicians involved in the care of people with this condition comprehensively approach the management and follow-up of the patients, and that they organize interdisciplinary teams including all the professionals that can help to increase the quality of life of patients. Read More on PubMed
  • To examine the long-term effects of suboccipito-cervical decompression on an intention-to-treat basis in patients with Chiari I malformation (CMI). Read More on PubMed
  • Surgery for Chiari malformation Type I (CM-I) is one of the most common neurosurgical procedures performed in children, although there is clearly no consensus among practitioners about which surgical method is preferred. The objective of this meta-analysis was to compare the outcome of posterior fossa decompression with duraplasty (PFDD) and posterior fossa decompression without duraplasty (PFD) for the treatment of CM-I in children. Read More on PubMed
  • Both the diagnosis and treatment regimens for the Chiari I malformation (CIM) are varied and controversial. The present paper analyzes the literature regarding this form of hindbrain herniation in regard to definition, anatomy, pathobiology, symptoms, findings, treatment, and outcomes. Read More on PubMed
  • While brain imaging in the clinical setting is largely a practice of looking at images, research neuroimaging is a quantitative and integrative enterprise. Images are run through complex batteries of processing and analysis routines to generate numeric measures of brain characteristics. Other measures potentially related to brain function - demographics, genetics, behavioral tests, neuropsychological tests - are key components of most research studies. The canonical scanner - PACS - viewing station axis used in clinical practice is therefore inadequate for supporting neuroimaging research. Here, we model the neuroimaging research enterprise as a workflow. The principal components of the workflow include data acquisition, data archiving, data processing and analysis, and data utilization. We also describe a set of open-source applications to support each step of the workflow and the transitions between these steps. These applications include DIGITAL IMAGING AND COMMUNICATIONS IN MEDICINE viewing and storage tools, the EXTENSIBLE NEUROIMAGING ARCHIVE TOOLKIT data archiving and exploration platform, and an engine for running processing/analysis pipelines. The overall picture presented is aimed to motivate open-source developers to identify key integration and communication points for interoperating with complimentary applications. Read More on PubMed
  • In face of continuing controversy to the optimal treatment of Chiari type I malformation, the authors analyzed three different surgical strategies. Read More on PubMed
  • The Extensible Neuroimaging Archive Toolkit (XNAT) is a software platform designed to facilitate common management and productivity tasks for neuroimaging and associated data. In particular, XNAT enables qualitycontrol procedures and provides secure access to and storage of data. XNAT follows a threetiered architecture that includes a data archive, user interface, and middleware engine. Data can be entered into the archive as XML or through data entry forms. Newly added data are stored in a virtual quarantine until an authorized user has validated it. XNAT subsequently maintains a history profile to track all changes made to the managed data. User access to the archive is provided by a secure web application. The web application provides a number of quality control and productivity features, including data entry forms, data-type-specific searches, searches that combine across data types, detailed reports, and listings of experimental data, upload/download tools, access to standard laboratory workflows, and administration and security tools. XNAT also includes an online image viewer that supports a number of common neuroimaging formats, including DICOM and Analyze. The viewer can be extended to support additional formats and to generate custom displays. By managing data with XNAT, laboratories are prepared to better maintain the long-term integrity of their data, to explore emergent relations across data types, and to share their data with the broader neuroimaging community. Read More on PubMed
  • For patients with lumbar disk herniation, the Spine Patient Outcomes Research Trial (SPORT) randomized trial intent-to-treat analysis showed small but not statistically significant differences in favor of diskectomy compared with usual care. However, the large numbers of patients who crossed over between assigned groups precluded any conclusions about the comparative effectiveness of operative therapy vs usual care. Read More on PubMed
  • To determine the prevalence of syringomyelia in a defined population in New Zealand and measure the prevalence of syringomyelia in the three main ethnic groups (Maori, Pacific people and Caucasians/others) living in this region. Read More on PubMed
  • In this retrospective analysis, the authors report a prospective study in which intraoperative ultrasonography was used to determine the extent of surgery necessary during posterior fossa decompression surgery for Chiari malformation Type I (CM-I) in children. Read More on PubMed
  • In the present review the author describes the different types of syringomyelia that originate from abnormalities at the level of the spinal cord rather than at the craniovertebral junction. These include posttraumatic and postinflammatory syringomyelia, as well as syringomyelia associated with arachnoid cysts and spinal cord tumors. The diagnosis and the principles of managing these lesions are discussed, notably resection of the entity restricting cerebrospinal fluid flow. Placement of a shunt into the syrinx cavity is reserved for patients in whom other procedures have failed or who are not candidates for other procedures. Read More on PubMed
  • Syringomyelia is characterized by the presence of cystic cavities inside the spinal cord, with an incidence estimated of 8.4 new cases/year/100 000 people. The cavities are usually located inside the cervical cord, although they can extend upwards and/or downwards. The underlying cause of all types of syringomyelia is an alteration in physiologic cerebrospinal fluid (CSF) flow dynamics. Four different main types may be described in descending order of frequency: associated with Chiari I malformations, associated with vertebral trauma, associated with basilar invagination and associated with hydrocephalus. Conservative treatment is not recommended as the surgical procedure stops the progress of the disease with clinical improvement being the rule. Early surgical treatment is highly recommended before the establishment of gross neurological deficits occurs. Treatment is urged in case of clinical deterioration or when the follow-up MRI studies show increase in size and extension of the syringomyelic cavity. The first step in the surgical treatment is a precise diagnosis of its etiology to direct the treatment to the underlying cause. Treatment directed to normalize CSF flow homeostasis should be case tailored. Surgical measures that aim to reconstruct the continuity of the subarachnoid space at the site of the block are the first treatment option. Shunting is advocated when reestablishment of the pathways proves impossible or as a second procedure. Read More on PubMed
  • The purpose of this prospective study was to determine if there was a difference in the self-perceived quality of life (QOL) before and after surgery among patients with Chiari I malformations with or without syringomyelia. Most patients with Chiari I malformations report improvement in their QOL after decompression surgery; however, specific outcome data have not been empirically studied in this patient population. Read More on PubMed
  • The choice of surgical technique for decompressive surgery in patients with Chiari I malformation is controversial. Good preliminary postoperative outcomes have been achieved in patients with Chiari I malformation (without syringomyelia) after using a dura-splitting technique. The authors evaluated safety, resource use, and early outcome after this surgery in patients without syringomyelia and compared the findings associated with duraplasty in patients with syringomyelia. Read More on PubMed
  • An increasing number of children with Chiari I malformations are coming to the attention of neurosurgeons today, although a consensus on the surgical approach to these lesions has yet to be found. Read More on PubMed
  • Since the introduction of MRI, the incidence of Chiari I malformations (cerebellar tonsils ectopia) has increased. The clinical significance of this finding remains questionable in some instances. Recently, cine flow MRI has added to the understanding of the dynamics of cerebrospinal fluid at the craniocervical junction and to the pathophysiology of the Chiari I malformation. The present study attempts to analyze the role of cine flow MRI in Chiari I malformations. Read More on PubMed
  • Children with complex chronic conditions (CCCs) might benefit from pediatric supportive care services, such as home nursing, palliative care, or hospice, especially those children whose conditions are severe enough to cause death. We do not know, however, the extent of this population or how it is changing over time. Read More on PubMed
  • The optimal surgical treatment of Chiari malformation is unclear, especially in patients with hydromyelia. Various surgical approaches have included suboccipital craniectomy, syringostomy, obex plugging, syringosubarachnoid shunting, and fourth ventriculosubarachnoid shunting. The purpose of this study is to differentiate extradural and intradural approaches in the treatment of Chiari I malformation. Read More on PubMed
  • Syringomyelia causes progressive myelopathy. Most patients with syringomyelia have a Chiari I malformation of the cerebellar tonsils. Determination of the pathophysiological mechanisms underlying the progression of syringomyelia associated with the Chiari I malformation should improve strategies to halt progression of myelopathy. Read More on PubMed
  • Most reports regarding pediatric syringomyelia have focused not only on Chiari malformation, but also on spinal dysraphism. However, the clinical characteristics of syringomyelia with spinal dysraphism are quite different from those of syringomyelia due to Chiari Type I malformation. The objectives of this study were to identify clinical characteristics of pediatric syringomyelia and to determine whether surgery prevents or corrects the scoliosis associated with syringomyelia. Read More on PubMed
  • The different measurement properties necessary for instruments whose goal is to detect differences between subjects at a single point in time (discriminative instruments) and those whose goal is to detect longitudinal change within subjects (evaluative instruments) is becoming increasingly recognized. Up to now, requirements for evaluative instruments have been presented as reproducibility, validity, and responsiveness (i.e. the ability to detect change over time). An alternative conceptualization would characterize any instrument as requiring two crucial measurement properties. One is validity, the other a high ratio of signal to noise. For discriminative instruments, the signal to noise ratio can be summarized in a reliability coefficient; for evaluative instruments, in a responsiveness index or coefficient. This formulation can simplify and clarify the understanding and teaching of issues in health status measurement. Read More on PubMed
  • Evaluation of evidence that treatment efficacy varies substantially among different subsets of patients is an important feature of the analysis of large clinical trials. Qualitative or crossover interactions are said to occur when one treatment is superior for some subsets of patients and the alternative treatment is superior for other subsets. A non-crossover interaction arises when there is variation in the magnitude, but not in the direction, of treatment effects among subsets. Some authors use the term quantitative interaction to mean non-crossover interaction. Non-crossover interactions are usually of less clinical importance than qualitative interactions, which often have major therapeutic significance. A likelihood ratio test is developed to test for qualitative interactions. Exact critical values are determined and tabulated. Read More on PubMed
  • Tests or measures in clinical medicine or the social sciences can be used for three purposes: discriminating between subjects, predicting either prognosis or the results of some other test, and evaluating change over time. The choices made at each stage of constructing a quality of life index will differ depending on the purpose of the instrument. We explore the implications of index purpose for each stage of instrument development: selection of the item pool, item scaling, item reduction, determination of reliability, of validity, and of responsiveness. At many of these stages, not only are the requirements for discriminative, predictive, and evaluative instruments not complementary, they are actually competing. Attention to instrument purpose will clarify the choices both for those developing quality of life measures and for those selecting an appropriate instrument for clinical studies. Read More on PubMed